Is there something around the house you can use to measure an ounce?

Answer 1

Fluid ounce, perhaps. In the US, the average whiskey-shot glass holds

1.25 to 1.5 fluid ounces, although there is no standard.

Ounce of weight ... we can't think of anything except a postage meter.

Answer 2

A standard shot glass typically holds about 1.5 ounces, so you can use that as a rough measurement for one ounce by eyeballing it carefully. Alternatively, a kitchen scale can provide a more precise measurement for an ounce of a solid ingredient.